Main Facts: Bridging the Tax Divide Between Mutual Funds and ETFs
American financial markets stand at a critical juncture, where the long-term economic trajectory of the nation is increasingly tied to the ease and efficiency of domestic investment. For decades, the tax treatment of investment returns has played a quiet yet powerful role in shaping how Americans allocate their savings. These tax structures can frequently act as unintended barriers to wealth accumulation.
Enter the Generating Retirement Ownership Through Long-Term Holding (GROWTH) Act—a bipartisan-backed legislative proposal introduced simultaneously in both chambers of Congress by Senator John Cornyn (R-TX) and Representative Beth Van Duyne (R-TX). The legislation is designed to correct a long-standing structural discrepancy in how different investment vehicles are taxed. Specifically, the GROWTH Act seeks to improve the tax treatment of domestic saving by allowing investors to defer capital gains taxes on qualifying reinvested capital gains distributions until they actually sell their fund shares.
To understand the core issue, one must look at the mechanics of two of the most popular retail investment vehicles: mutual funds and exchange-traded funds (ETFs). While both types of funds are legally subject to the same tax rules as regulated investment companies (RICs), they operate and process redemptions in fundamentally different ways. These operational differences yield starkly divergent tax outcomes for ordinary shareholders.
Conventional mutual funds manage redemptions internally. When a shareholder decides to cash out a portion of their mutual fund holdings, the fund manager may be forced to sell underlying stocks to raise the necessary liquidity. If those stocks have appreciated significantly since purchase, the sale triggers a capital gains realization. Crucially, under current law, this net capital gain is distributed to the remaining fund shareholders rather than being taxed inside the fund itself. As a result, investors who have not sold a single share of their mutual fund can suddenly find themselves owing capital gains taxes on profits they never realized in cash.
In contrast, exchange-traded funds operate on a secondary market mechanism. Retail ETF shareholders buy and sell shares directly with one another on public exchanges rather than redeeming them through the fund. When large institutional players—known as authorized participants—redeem blocks of ETF shares, they typically execute "in-kind" transactions, swapping shares for a basket of underlying securities. Crucially, these in-kind redemptions do not trigger capital gains realizations that get passed along to remaining retail investors.
Consequently, two investors holding virtually identical portfolios through different fund structures can experience wildly different tax liabilities. While mutual fund investors can face recurring tax bills simply because other investors are redeeming shares, ETF investors do not face this phantom tax liability while holding their positions. Real-world data underscores this imbalance: average capital gains distributions are markedly higher for mutual funds than for ETFs, directly suppressing the after-tax returns of mutual fund holders.
The GROWTH Act addresses this disparity head-on. By allowing investors to defer recognition of qualifying reinvested capital gains until they liquidate their fund shares, the legislation harmonizes the timing of capital gains taxation between mutual fund and ETF shareholders. Dividend and interest income, however, would continue to be taxed under existing statutory rules.
Chronology: The Path to Legislative Reform
The introduction of the GROWTH Act is the culmination of years of growing academic and industry scrutiny regarding competitive distortions in the U.S. asset management landscape.
- Early 2010s–2020: The explosive growth of exchange-traded funds began to highlight structural tax advantages over traditional mutual funds. As more retail capital shifted toward passive indexing and ETFs, financial economists and tax experts increasingly pointed out the unfairness of "phantom" capital gains distributions burdening mutual fund buy-and-hold investors.
- September 2025: Comprehensive industry data published in the Investment Company Institute (ICI) Factbook provided updated baselines, confirming that mutual funds continued to account for the vast majority of capital gains distributions relative to alternative vehicles, with high reinvestment rates hovering around 96 percent.
- Late 2025 / Early 2026: Economic modelers and think tanks, including the Tax Foundation, intensified research into the macroeconomic consequences of tax-induced asset distortions. Policy papers from organizations like the Brookings Institution further outlined potential legislative pathways to reform the taxation of index funds, mutual funds, and ETFs.
- Current Legislative Session (2026): Senator John Cornyn and Representative Beth Van Duyne formally introduced the GROWTH Act in both chambers of Congress. The bill was drafted to address horizontal equity, neutralize tax code biases, and encourage long-term domestic savings.
- September 2026: The Tax Foundation released its comprehensive General Equilibrium Model scoring of the GROWTH Act, projecting its conventional revenue impacts, distributional effects on after-tax incomes, and long-run economic consequences over the 2027–2036 budget window.
Supporting Data: Economic Modeling and Revenue Effects
Any major alteration to the federal tax code requires rigorous economic scoring to project its impact on the federal budget and American households. According to the Tax Foundation’s General Equilibrium Model released in September 2026, the GROWTH Act is projected to reduce federal revenue by $37.7 billion on a conventional basis between 2027 and 2036.
Table 1. Conventional Revenue Effects of the GROWTH Act Mutual Fund Capital Gains Deferral
Billions of Dollars, 2027–2036
- Budget Window Dynamics: Like many proposed timing changes in tax policy, the fiscal cost of the GROWTH Act is heavily front-loaded. In the initial years, reinvestment amounts that were previously subject to immediate capital gains taxation become eligible for deferral, yet few of those deferred amounts have been sold yet.
- Steady-State Cost: As deferred amounts are eventually realized and sold over time, the net annual cost drops substantially. By the latter part of the budget window, the annual revenue loss settles just above $1 billion per year, indicating a manageable long-run fiscal profile.
It is worth noting that this conventional revenue estimate does not account for the compounding effect of reinvested returns. Because the reinvested returns that make up deferred tax liabilities can themselves compound and eventually be subject to tax upon sale, the true long-run conventional revenue cost may be somewhat lower than the initial scored estimate.
Distributional Analysis Across Income Spectra
The legislation also carries notable distributional impacts, albeit ones that phase down over time.
Table 2. Conventional Distributional Effects of the GROWTH Act
Percent Change in After-Tax Market Income
- Initial Year Impact (2027): On average, the GROWTH Act would increase after-tax incomes by approximately 0.1 percent across the income spectrum as investors retain capital that would have otherwise gone toward immediate tax liabilities.
- Long-Term Impact (2036): By the end of the decade-long budget window, changes in annual tax liabilities moderate, leading to an increase of less than 0.05 percent in after-tax incomes.
(Note: Market income metrics incorporate adjusted gross income (AGI) plus tax-exempt interest, non-taxable Social Security, employer payroll tax shares, imputed corporate tax liabilities, fringe benefits, and defined-contribution pension contributions, adjusted for tax unit size.)
Official Responses and Stakeholder Perspectives
The introduction of the GROWTH Act has generated significant discussion among lawmakers, tax policy experts, and financial industry stakeholders. Proponents emphasize the fundamental fairness of the measure, while fiscal analysts weigh the trade-offs between tax neutrality and short-term revenue losses.
The Case for Neutrality
Sponsors of the legislation, including Sen. Cornyn and Rep. Van Duyne, have framed the bill as a common-sense modernization of the tax code. From a strict economic neutrality perspective, tax codes should be engineered so that investors make decisions regarding underlying assets and fund vehicles strictly on their economic merits rather than attempting to game tax outcomes.
Under current law, the tax penalty inherent to mutual fund structures distorts consumer choice, pushing investors away from traditional mutual funds—even when those funds might otherwise offer superior management strategies, liquidity terms, or fee structures. By leveling the playing field, the GROWTH Act ensures that identically situated investors across different fund types face comparable tax liabilities.
Fiscal and Economic Trade-Offs
While tax experts generally praise the bill’s pursuit of horizontal equity, they also point out inherent trade-offs. By expanding the scope of tax deferral within the individual income tax code, the proposal inherently encourages taxpayers to slow down their pace of capital gains realizations—a phenomenon known in economics as the "lock-in effect."
The lock-in effect can occasionally pose economic challenges by discouraging investors from liquidating appreciated assets, potentially preventing capital from flowing toward newer, more productive uses in the broader economy. However, policy analysts note that the proposal’s built-in safeguards—specifically rules preventing taxpayers from avoiding tax altogether via the step-up in basis—successfully mitigate the worst incentives of this lock-in behavior.
Implications: Long-Run Economic Growth and Future Reform
The passage and implementation of the GROWTH Act would carry profound implications for individual savers, institutional asset managers, and the broader U.S. economy.
Boosting Gross National Product (GNP)
By reducing the tax drag on investment returns, the GROWTH Act directly increases the after-tax returns to saving. Economic theory dictates that higher returns on saving encourage greater capital accumulation. Over the long run, this dynamic would lead to an expansion in Gross National Product (GNP), which measures the total income earned by American residents.
However, economists caution that the net economic benefit of the legislation depends heavily on how the resulting federal revenue loss is financed. If the $37.7 billion revenue reduction is financed through additional federal borrowing, the resulting increase in national debt would drive up interest payments to foreign investors. This capital outflow could offset a portion of the domestic income gains realized by American households.
Broader Horizons in Capital Taxation
While the GROWTH Act represents a targeted, highly constructive improvement in tax neutrality, tax policy organizations view it as a stepping stone rather than a final destination. Larger, more comprehensive reforms to the tax treatment of saving and investment—such as universal savings accounts or a broader shift toward consumption-based taxation—would be required to completely remove systemic distortions in the taxation of capital gains.
Ultimately, the ideal tax code should play a minimal role in influencing how taxpayers invest and which financial vehicles they choose. By eliminating the tax penalty traditionally associated with mutual fund structures, the GROWTH Act moves the United States one step closer to a fairer, more efficient, and economically neutral financial ecosystem.
